Atrial fibrillation and QT corrected. What is the best formula to use?

BACKGROUND: QT interval varies with the heart rate (HR), so a correction in QT calculation is needed (QTc). Atrial fibrillation (AF) is associated with elevated HR and beat-to-beat variation. AIM: To find best correlation between QTc in atrial fibrillation (AF) versus restored sinus rhytm (SR) after electrical cardioversion (ECV) (primary end point) and to determine which correction formula and method are the best to determine QTc in AF (secondary end point). METHODS: During a 3-month period, we considered patients who underwent 12-lead ECG recording and received an AF diagnosis with indication for ECV. Exclusion criteria were as follows: QRS duration >120 ms, therapy with QT-prolonging drugs, a rate control strategy and a nonelectrical cardioversion. The QT interval was corrected using Bazzett's, Framingham, Fridericia and Hodges formulas during the last ECG during AF and the first one immediately after ECV. QTc mean was calculated as mQTc (average of 10 QTc calculated beat per beat) and as QTcM (QTc calculated from the average of 10 raw QT and RR for each beat). RESULTS: Fifty consecutive patients were enrolled in the study. Bazett's formula showed a significant change in mean QTc value between the two rhythms (421.5 ± 33.9 vs. 446.1 ± 31.9; p < 0.001 for mQTc and 420.9 ± 34.1 vs. 441.8 ± 30.9; p = 0.003 for QTcM). On the contrary, in patients with SR, QTc assessed by the Framingham, Fridericia, and Hodges formulas was similar to that in AF. Furthermore, good correlations between mQTc and QTcM are present for each formula, even in AF or SR. CONCLUSIONS: During AF, Bazzett's formula, seems to be the most imprecise in QTc estimation.

Nonbacterial Thrombotic Endocarditis with Atypical Presentation as Overt Congestive Heart Failure.

Nonbacterial thrombotic endocarditis (NBTE) is a form of endocarditis associated with malignancy or autoimmune disorders. Diagnosis remains a challenge as patients are often asymptomatic up to embolic events or rarely, valve dysfunction. We report a case of NBTE with uncommon clinical presentation and identified with multimodal echocardiography. An 82-year-old man presented to our outpatient clinic reporting dyspnea. Past medical history included hypertension, diabetes, kidney disease, and unprovoked deep-vein thrombosis. On physical examination, he was apyretic, mildly hypotensive, and hypoxemic, had a systolic murmur and lower limbs edema. Transthoracic echocardiography revealed severe mitral regurgitation due to verrucous thickening of the free margin of both leaflets, increased pulmonary pressure, and dilated inferior vena cava. Multiple blood cultures were negative. Transesophageal echocardiography confirmed "thrombotic" thickening of mitral leaflets. Nuclear investigations were highly suggestive of multi-metastatic pulmonary cancer. We did not further proceed with the diagnostic workup and prescribed palliative care. Lesions seen on echocardiography were suggestive of NBTE: they involved both sides of mitral leaflets, close to the edges, had irregular shape and echo density, a broad base, and no independent motion. Criteria for infective endocarditis were not met and the final diagnosis was paraneoplastic NBTE due to underlying lung cancer. We remark the lack of definitive recommendations about the treatment of NBTE and the only role of anticoagulation to prevent systemic embolism. We have reported a case of NBTE presenting with atypical symptoms and likely related to the prothrombotic state induced by underlying lung cancer. Provided the unconclusive microbiological tests, multimodal imaging has played a crucial role in the final diagnosis.